As the study of human physiology and anatomy clearly demonstrates, the relative simple action of walking on an even flat surface involves numerous biomechanical complexities. A single step requires constant biofeedback such as continual analysis of proprioception, angulations, timing, and balanced muscular-skeletal functions. In the prior art, the prosthetic industry is continuously attempting to mimic natural human locomotion (NHL), performance and aesthetics.
The field of prosthetics, in general, has made enormous advances in improving amputee and congenitally deformed individuals' performance on multiple levels from general ambulation to competitive sports through improved technology and understanding of human biomechanics. Although, it is known in the art to manufacture ankle and foot prosthetic combinations that have generally increased performance and appearance, the prior art is still deficient on numerous levels as will be discussed in greater detail below.
Many prosthetic feet are optimized for a small or limited range of activities. Typically, models aligned for such activities as daily walking are not optimally aligned for running and vice versa. It is, therefore, desirable to provide a design that allows a user to go from walking to running to provide greater user flexibility in multiple activities. Furthermore, while prior art prosthetic devices may have generally moved amputees toward more biomechanically appropriate gait patterns, current mechanically controlled designed prosthetic feet do not allow for significant alterations in gait speed without losing optimal biomechanical characteristics essential with walking or running. Still furthermore, it is desirable to provide a design that allows transition from flat ground to moving up hill or from flat ground to moving downhill with ease, safety, function, and generally traversing uneven surfaces, where the prior art is lacking.
There are models in the prior art that are characterized by the term ENERGY STORING that may provide greater energy return than other models through spring-return characteristics of the keel members to lessen energy expenditures. Additionally, models that provide MULTI-AXIAL uneven ground accommodation have been developed to better assist users to gain better balance on real-world environments. Unfortunately, neither of these categories of advancements provides both optimal energy return and uneven ground accommodation sufficiently to meet user needs in all activities and in all environments. While numerous prosthetic feet and ankle systems are available in the market, no mechanical based prosthetics provide full mimicking of their anatomical counterpart. It is now contemplated that optimal biomechanical and natural human locomotion functions cannot come solely through a relative simple mechanical device such as found in much of the existing prior art.
By example in non-ankle and foot prosthetics, it has been observed in a microprocessor controlled C leg knee design by the company OTTO BOCK that amputees are able to have better gait symmetry, decreased energy expenditure, and a much greater sense of mental confidence in ambulating than non-microprocessor prosthetic knees, however, there remains a significant gap between the most advanced prosthetics and the human body. Therefore, there remains a need to greatly improve the functional abilities of the prosthetic system, and hence, the abilities of the amputee. It is now contemplated that similar benefits could be observed through this type of design but for a broader spectrum of amputees, including trans-tibial amputees, through the use of a computer controlled prosthetic ankle and foot system with appropriate sensory feedback mechanisms. Through this disclosure, an improved prosthetic control system is discussed which more closely mimics the natural control functions of the human body.
Another consideration lacking in the prior art of ankle and foot devices is the combination of aesthetics and function. It is desirable to provide a prosthetic foot that also has a much more cosmetic effect through better simulating proper natural human locomotion and allows the foot to plantarflex during sitting to better simulate a real ankle and foot. In this manner, a user's foot and ankle would appear more normal than the telltale sign of a prosthetic that juts unnaturally up when sitting.
Oftentimes, aesthetics is sacrificed for increased function. A common complaint of many prosthetic foot users, for instance is that their prosthetic foot “sticks up” with unnatural dorsiflexion angle when they sit. This remains a problem due to the prior art prosthetic feet being relatively affixed at a given angle with respect to the prosthesis, thus, during sitting the foot remains pointing upwards as the shin section of the prosthesis has a posterior lean when the amputee is sitting. This is a major complaint of many prosthetic users, and has not been adequately addressed through commercially available prosthetics.
The OSSUR Proprio Foot design does allow for plantarflexion during sitting, however, it is does not take place in an aesthetically natural manner. After a few moments after sitting, the foot then plantarflexes through powered actuation. The design disclosed in this patent has the ability to naturally, and immediately plantarflex during sitting, accommodating for the natural angle of the shin with respect to the ground.
With robotics and advanced prosthetics, it is essential that the motion of the bio-replicating design match the natural movement of the anatomical counterpart in great detail. As the realistic nature of the prosthesis approaches that of the natural limb, in cosmetic physically and biomechanically similar characteristics, the psychological acceptance of the device becomes increasingly difficult. When a bio-resembling robotic device or advanced prosthesis offers enough dissimilarities from the natural limb, the psyche recognizes that it is not real and readily accepts the device, though the prosthetics user is often dissatisfied with the capabilities of the device by not replicating the body well enough. When the robotic or prosthetic device, however, approaches the upper limits of realism, a psychological effect referred to as the “Uncanny Valley” syndrome occurs, resulting in the user's dissatisfaction with the device, though it is more life-like than less biomechanically similar counterparts. It is imperative that the realistic nature of the advanced design illustrated here is capable of being fine-tuned to the natural movement of the user, in all conditions and in all environments, whereas to allow for full mental acceptance of the design being integrated as an accessory extension of the body. This disclosed design, unlike other prosthetics available in the field today, offers much more life-like appearance than conventional technology, such as in plantarflexion during sitting, and allows for fine-tuned adjustments of the movement to prevent the Uncanny Valley syndrome with respect to prosthetic acceptance.
Furthermore, the stubbing of a prosthetic foot has proven to be a safety issue for trans-tibial, trans-femoral, and hip-disarticulation amputees alike at all activity levels. This often occurs because many conventional prosthetic feet do not dorsiflex during the swing phase of gait, as occurs naturally. The prior art prosthetic feet have attempted to dorsiflex the foot during swing phase in the past, such as with the a prior art design under the trademark or name HYDROCADANCE, but have generally failed to provide the full range of benefits desired, such as being able to be used on a vast array of lower extremity amputees' functional abilities and amputation levels as well as provide optimal energy return characteristics, range of motion, and a life-like appearance, to name a few. The OSSUR Proprio Foot does allow for dorsiflexion during the swing phase of gait, but is unable to appropriately accommodate for the necessary dorsiflexion angle correlating to the terrain angle. Additionally, its dorsiflexion ability, and other movement characteristics, takes place over a series of steps, but does not occur in real-time, as this design does.
Still furthermore, it is desirable to have a functional prosthetic that may also allow a user to choose from various cosmetically shaped foot shells where the prior art fails. Though prosthetic feet are not commonly seen because they are frequently covered by shoes, cosmetic appearance is a very important aspect to many amputees and other users due to current lifestyle and fashion trends. It is therefore desirable to provide a device that may allow several foot shell templates to choose from or to have customized foot shell molds fabricated much like what is now available with upper extremity prosthetics cosmetic gloves.
What is needed is a prosthetic design utilizing electronics such as but not limited to a prosthetic microprocessor, sensory feedback mechanisms for various angle, time, and moment or pressure sensors, and actively providing a means for adjusting plantarflexion and dorsiflexion through prosthetic proprioception which will allow a user to transverse all necessary barriers with appropriate biomechanical precision, stability, and range of activities.
Furthermore, it is desirable to provide a design for a very active user who may want to perform daily activities and run, and which provides additional stability and safety for lower activity users who simply need to traverse low level barriers with enhanced safety and stability.
Still furthermore, one of the areas of prosthetics that is very much at its infancy stages is creating prosthetic sensory feedback mechanisms. It is believed that the better the mesh between the human and machine interactions, the more functional, safe, and life-like a user's abilities will become.
Currently found in prosthetic systems used today or in prosthetic research laboratories is the sense of feel system which generally attempts to correspond to human tactile receptors in extremities. The prosthesis detects pressure and stimulates the residual limb in a manner to trick the brain into thinking it is “feeling” with the prosthesis through cerebral projections. In essence, the prosthesis attempts to communicate or provide feedback to the user's brain.
Furthermore, there is also myoelectric control, which generally attempts interaction from muscular control of extremity muscles. The electrical activity from the muscular actions within the residual limb is picked up by electrodes embedded in, by example, the socket system and cause the prosthetic hand to move in an intended manner. In essence, the brain attempts to communicate or provide feedback to the prosthesis.
Still furthermore, it is understood to attempt a general prosthetic brain wherein correspondence to a sort or proprioception by having the microprocessor embedded in the prosthesis, along with an array of various sensors, cause the prosthetic joint to move in a fashion that matches up to the wearer's gait pattern and/or intended movement. By example in the prior art, the C-leg system uses a microprocessor or prosthetic brain to constantly analyze how fast it should flex and extend during the swing phase of gait, as well as how much stance stability to maintain during the stance phase of gait, amongst other actions. Such design generally mimics the motion of the sound limb independent of the terrain or slope, according to a pre-set determined set of variables. While this design does adjust its stance and swing characteristics, it does not provide do so in accordance with the anatomical limb's natural movement in all conditions and in all environment, and not in a full bio-replicating manner.
Although prosthetic technology has advanced in recent years, the prior art still has failed to bridge the gap between man-made prosthetics and user demand and needs. Likewise, there is also a desire to enhance the body/prosthesis integration through sensory feedback mechanisms and prosthetic proprioception. Therefore, an extensive opportunity for design advancements and innovation remains where the prior art fails or is deficient.